Tumbler mechanism for cylinder lock

ABSTRACT

A tumbler mechanism for a cylinder lock is provided having a first tumbler element normally extending into a key slot, a second tumbler element normally engaging the first tumbler element for retaining it in the key slot, a bore passing through the second tumbler element, a pin passing through the bore for engaging the first tumbler element and a spring for biasing said pin to push the first tumbler element into the key slot in the event that the second tumbler element becomes jammed.

United States Patent [1 1 Prahl I [451 Mar. 11, 1975 1 TUMBLER MECHANISM FOR CYLINDER LOCK [76] Inventor: Herman Prahl, 43-38th Fifty-Eighth Ln., Woodside, N.Y. 11377 [22] Filed: June 18, 1973 [21] Appl. No.: 370,657

[52] US. Cl 70/419, 70/359, 70/364 A [51 Int. Cl E05b 63/00 [58] Field of Search 70/359, 364 A, 419, 421,

[56] References Cited UNITED STATES PATENTS 11/1935 Williams 70/421 3/1940 Voight 38 s t/ i /t7 it P1 2,653,467 9/1953 Segal 70/359 Primary Examiner-Robert L. Wolfe Attorney, Agent, or Firm-Harvey Zeller [57] ABSTRACT 11 Claims, 3 Drawing Figures e g? & w =5 226 O 1 TUMBLER MECHANISM FOR CYLINDER LOCK BACKGROUND OF THE INVENTION The present invention relates to cylindrical locking mechanisms and particularly to a pick-proof tumbler mechanism for a cylinder lock.

In recent years, lock security has become increasingly important. As a result, cylinder locks which offer greater security than normal spring locks have gained in popularity. In spite of the added security which these locks offer it is still possible to pick these locks by jamming the internal tumbler pins sequentially in their retracted positions.

It is therefore an object of the present invention to provide an improved tumbler mechanism making it impossible to pick the lock in which it is used by jamming.

It is another object of the present invention to provide a tumbler mechanism which prevents sequential picking of the tumbler elements within the lock.

SUMMARY OF THE INVENTION The above objects are accomplished by the present invention by means of a tumbler mechanism which briefly includes a first tumbler element which normally extends into the key slot, a second tumbler element normally engaging the first tumbler element for retaining it in the key slot while also intersecting the cylindrical plane between the key plug and the cylinder housing therefor, a bore passing through the second tumbler element, a pin passing through the bore also engaging the first tumbler element and a spring arrangement for biasing the pin to push the first tumbler element into the slot in the event that the second tumbler element becomes jammed. The action of the pin causing the first tumbler element to re-enter the key slot prevents sequential picking of the tumbler elements and additionally serves to intersect the cylindrical plane between the key plug and its housing to prevent rotation of the key plug in the housing and thus operation of the lock.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view ofa cylinder lock employing the tumbler mechanism of the instant invention;

FIG. 2 is an enlarged cross-sectional view of one tumbler mechanism of the instant invention showing portions of the key plug and housing; and

FIG. 3 is an enlarged cross-sectional view of a tumbler mechanism of the instant invention when the interior tumbler has been jammed and the key has been removed from the key slot.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings and particularly to FIG. 1, there is shown a cylinder lock generally indicated as having a cylindrical housing 12 and a key plug 14 for rotation therein by a key 16. The housing and key plug 14 have aligned rows of tumbler holes l8a,b,c,d,e and a.h,c,d,e, respectively. Within these holes are tumbler elements 22a,b,c,d,e and 24a,b,c,d,e. When the tumbler elements are in the positions shown in FIG. 1 such that all of the tumbler elements 22a,b,c,d,e abut respective tumbler elements 24a,b,c,d,e in a cylindrical plane 26 between cylindrical housing 12 and key plug 14, the key plug 14 may be rotated with respect to the housing 12 to operate the lock 10.

Referring next to FIG. 2, there is shown an enlarged view of the tumbler mechanism of the instant invention. The elements of FIG. 2 have been given the same designations as the corresponding elements of FIG. I with the subscript a for illustrative purposes. As shown, in addition to tumbler elements 22a and 24a, the tumbler mechanism includes a pin 28a passing through a bore 30a axially extending through tumbler element 240. Pin 28a has a head 32a at one end thereof located in bore 18a between springs 34a and 36a, spring 34a being situated between head 32a and tumbler element 24a and spring 360 being situated between head 32a and a retaining plate 38. Under normal conditions without a key in the key slot, springs 34a and 36a combine to bias pin 28a and tumbler element 24a into engagement with tumbler element 22a forcing the latter into the key slot whereby the engaging surfaces of tumbler elements 22a and 240 are out of alignment with cylindrical plane 26 thus preventing rotation of the key plug 14 in housing 12.

FIG. 3 shows the tumbler mechanism in its operative condition when the upper tumbler element 24a has been jammed as, for instance, by the insertion of a key in the key slot and partial rotation of the key plug 14 within the housing 12 followed by removal of the key or where a pin is used to move the tumbler elements followed by partial rotation of the key plug to jam tumbler element 24a. In the operative condition of FIG. 3, spring 360 exerts a greater force on pin head 32a thus biasing pin 28a into engagement with tumbler element 220 forcing the latter into the key slot. This provides double protection against picking the lock. In the first place, since tumbler element 22a is forced back into the key slot, the line of vision to the next tumbler element 22b is blocked preventing it from being picked. Secondly, pin 280 extends across cylindrical plane 26 blocking rotation of the key plug 14 in housing 12 thereby preventing operation of the lock.

From the above, it should be clear that the present invention achieves a tumbler mechanism which prevents sequential picking of the tubmler elements of a cylinder lock and further prevents picking of the lock by jamming the tumbler elements.

While the present invention has been described with respect to a preferred embodiment thereof, modifications thereof within the spirit of the invention will now become apparent to those of ordinary skill in the art. It is thus intended that the scope of the invention not be limited by the illustrative embodiment described herein but rather by the claims appended hereto.

What is claimed is:

l. A tumbler mechanism for a cylinder lock comprisa first tumbler element extending into a key slot for movement upon the insertion of a key into said key slot;

a second tumbler element for axially aligning with said first tumbler element and moveable thereby upon the insertion of said key in said key slot;

a bore axially passing through said second tumbler element; a pin element passing through said bore for engaging said first tumbler element and moveable thereby upon the insertion of a key in said key slot, said pin element having an enlarged head portion at its end opposite its end engaging said first tumbler element and having a stem portion extending therefrom which engages said first tumbler element, said stem portion having a smaller crosssectional area than the cross-sectional area of said first tumbler element at their respective engaging surfaces; and

means for resiliently biasing said pin element for moving said pin element relative to said second tumbler element and tending to push said first tumbler element into said key slot.

2. A tumbler mechanism as defined in claim 1 wherein said biasing means is a first spring engaging said head.

3. A tumbler mechanism as defined in claim 2 further including a second spring between said head of said pin and said second tumbler element for normally biasing said second tumbler element into engagement with said first tumbler element tending to push said first tumbler element into said key slot.

4. A tumbler mechanism as defined in claim 3 wherein said first spring is stronger than said second spring whereby said first spring exerts a force on said pin sufficient to overcome said second spring to push said first tumbler element into said key slot if said second tumbler element becomes jammed in the position in which it has been moved in response to the insertion of a key in said key slot.

5. A cylinder lock having a cylindrical housing, a cylindrical bore longitudinally passing through said housing, a key plug passing through said cylindrical bore, a plurality of tumbler holes in said cylindrical housing and a plurality of tumbler holes in said key plug in alignment with said tumbler holes in said cylindrical housing and a key slot in said key plug comprising:

first tumbler elements in said tumbler holes in said key plug for extending into said key slot and moveable in response to the insertion ofa key in said key slot;

second tumbler elements in said tumbler holes in said cylindrical housing for engaging said first tumbler elements and extending into said tumbler holes in said key plug in the absence of a key in said key plug, said second tumbler elements being moveable by said first tumbler elements to positions removed from said key plug in response to the insertion of a key in said key slot;

bores in said second tumbler elements axially extending therethrough;

pin elements passing through said bores in said second tumbler element for engaging said first tumbler elements and moveable thereby in response to the insertion ofa key in said key slot, said pin elements having enlarged head portions at their respective ends opposite their ends engaging said first tumbler elements and having stem portions extending therefrom which engage said first tumbler elements, said stem portions having smaller crosssectional areas than the cross-sectional areas of said first tumbler elements at their respective engaging surfaces; and

means for resiliently biasing said pin elements for moving said pin elements relative to said second tumbler elements to push said first tumbler elements into said key slot in the event that said second tumbler elements become jammed in their positions removed from said key plug after removal of said key from said key slot.

6. A cylinder lock as defined in claim 5 wherein said biasing means are first springs engaging said pin element heads, respectively.

7. A cylinder lock as defined in claim 6 further including second springs between said respective pin heads and said respective second tumbler elements for normally biasing said second tumbler elements into engagement with respective ones of said first tumbler elements tending to push said first tumbler elements into said key slot and tending to push said second tumbler elements partially into said key plug.

8. A cylinder lock as defined in claim 7 wherein said first springs are stronger than said second springs whereby said first springs exert sufficient force on said pins to overcome said second springs to push said first tumbler elements into said key slot if said second tumbler elements become jammed in their positions removed from said key plug after the removal of said key from said key slot and to push said pins into said key plug to prevent rotation of said key plug in said cylindrical housing.

9. A cylinder lock as defined in claim 8 wherein said second tumbler elements are substantially mushroom shaped.

10. A tumbler mechanism for a cylinder lock comprising:

a first tumbler element extending into a key slot for movement upon the insertion of a key into said key slot;

a second tumbler element for axially aligning with said first tumbler element and moveable thereby upon the insertion of said key in said key slot;

a bore axially passing through said second tumbler element;

a pin element passing through said bore for engaging said first tumbler element and moveable thereby upon the insertion of a key in said key slot having a head at its end opposite the end engaging said first tumbler element;

first spring means engaging said head for resiliently biasing said pin element for moving said pin element relative to said second tumbler element and tending to push said first tumbler element in said key slot; and

a second spring between said head of said pin and said second tumbler element for normally biasing said second tumbler element into engagement with said first tumbler element tending to push said first tumbler element into said key slot.

1 l. A cylinder lock having a cylindrical housing, a cylindrical bore longitudinally passing through said housing, a key plug passing through said cylindrical bore, a plurality of tumbler holes in said cylindrical housing and a plurality of tumbler holes in said key plug in alignment with said tumbler holes in said cylindrical housing and a key slot in said key plug comprising:

first tumbler elements in said tumbler holes in said key plug for extending into said key slot and moveable in response to the insertion ofa key in said key slot;

second tumbler elements in said tumbler holes in said cylindrical housing for engaging said first tumbler elements and extending into said tumbler holes in said key plug in the absence of a key in said key plug, said second tumbler elements being moveable by said first tumbler elements to positions removed from said key plug in response to the insertion of a key in said key slot;

bores in said second tumbler elements axially extending therethrough;

pin elements passing through said bores in said second tumbler elements for engaging said first tumbler elements and moveable thereby in response to the insertion of a key in said key slot, said pin elements having heads at their ends opposite the ends engaging said first tumbler elements;

first springs engaging said heads for resiliently biasing said pin elements for moving said pin elements relative to said second tumbler elements to push said elements partially into said key plug.

* k F i 

1. A tumbler mechanism for a cylinder lock comprising: a first tumbler element extending into a key slot for movement upon the insertion of a key into said key slot; a second tumbler element for axially aligning with said first tumbler element and moveable thereby upon the insertion of said key in said key slot; a bore axially passing through said second tumbler element; a pin element passing through said bore for engaging said first tumbler element and moveable thereby upon the insertion of a key in said key slot, said pin element having an enlarged head portion at its end opposite its end engaging said first tumbler element and having a stem portion extending therefrom which engages said first tumbler element, said stem portion having a smaller cross-sectional area than the cross-sectional area of said first tumbler element at their respective engaging surfaces; and means for resiliently biasing said pin element for moving said pin element relative to said second tumbler element and tending to push said first tumbler element into said key slot.
 2. A tumbler mechanism as defined in claim 1 wherein said biasing means is a fiRst spring engaging said head.
 3. A tumbler mechanism as defined in claim 2 further including a second spring between said head of said pin and said second tumbler element for normally biasing said second tumbler element into engagement with said first tumbler element tending to push said first tumbler element into said key slot.
 4. A tumbler mechanism as defined in claim 3 wherein said first spring is stronger than said second spring whereby said first spring exerts a force on said pin sufficient to overcome said second spring to push said first tumbler element into said key slot if said second tumbler element becomes jammed in the position in which it has been moved in response to the insertion of a key in said key slot.
 5. A cylinder lock having a cylindrical housing, a cylindrical bore longitudinally passing through said housing, a key plug passing through said cylindrical bore, a plurality of tumbler holes in said cylindrical housing and a plurality of tumbler holes in said key plug in alignment with said tumbler holes in said cylindrical housing and a key slot in said key plug comprising: first tumbler elements in said tumbler holes in said key plug for extending into said key slot and moveable in response to the insertion of a key in said key slot; second tumbler elements in said tumbler holes in said cylindrical housing for engaging said first tumbler elements and extending into said tumbler holes in said key plug in the absence of a key in said key plug, said second tumbler elements being moveable by said first tumbler elements to positions removed from said key plug in response to the insertion of a key in said key slot; bores in said second tumbler elements axially extending therethrough; pin elements passing through said bores in said second tumbler element for engaging said first tumbler elements and moveable thereby in response to the insertion of a key in said key slot, said pin elements having enlarged head portions at their respective ends opposite their ends engaging said first tumbler elements and having stem portions extending therefrom which engage said first tumbler elements, said stem portions having smaller cross-sectional areas than the cross-sectional areas of said first tumbler elements at their respective engaging surfaces; and means for resiliently biasing said pin elements for moving said pin elements relative to said second tumbler elements to push said first tumbler elements into said key slot in the event that said second tumbler elements become jammed in their positions removed from said key plug after removal of said key from said key slot.
 6. A cylinder lock as defined in claim 5 wherein said biasing means are first springs engaging said pin element heads, respectively.
 7. A cylinder lock as defined in claim 6 further including second springs between said respective pin heads and said respective second tumbler elements for normally biasing said second tumbler elements into engagement with respective ones of said first tumbler elements tending to push said first tumbler elements into said key slot and tending to push said second tumbler elements partially into said key plug.
 8. A cylinder lock as defined in claim 7 wherein said first springs are stronger than said second springs whereby said first springs exert sufficient force on said pins to overcome said second springs to push said first tumbler elements into said key slot if said second tumbler elements become jammed in their positions removed from said key plug after the removal of said key from said key slot and to push said pins into said key plug to prevent rotation of said key plug in said cylindrical housing.
 9. A cylinder lock as defined in claim 8 wherein said second tumbler elements are substantially mushroom shaped.
 10. A tumbler mechanism for a cylinder lock comprising: a first tumbler element extending into a key slot for movement upon the insertion of a key into said key slot; a second tumbler element for axially aligning with said first tumbler element and moveable thereby upon the insertion of said key in said key slot; a bore axially passing through said second tumbler element; a pin element passing through said bore for engaging said first tumbler element and moveable thereby upon the insertion of a key in said key slot having a head at its end opposite the end engaging said first tumbler element; first spring means engaging said head for resiliently biasing said pin element for moving said pin element relative to said second tumbler element and tending to push said first tumbler element in said key slot; and a second spring between said head of said pin and said second tumbler element for normally biasing said second tumbler element into engagement with said first tumbler element tending to push said first tumbler element into said key slot. 